In the FW190 A8 aircraft handbook it states "when it is retracted, approximately one half of the tailwheel remains exposed and so can serve as an emergency tail skid".
When you look at the construction of the tail unit and how much of it is taken up with the mechanism for the tail wheel you...
I don't think that 4 separate engines were considered until the 488, and then they were the BMW 801 radials due to problems with the planned Jumo 222 engines. I can't find anything to suggest that 605's were considered at all - maybe Me 109/110 production took priority?
That looks like one of the B-17's that was turned into a drone, packed with explosives and modified like that so that the pilot could easily bail out.
I can't remember the name of the program without Googling, and wasn't there someone famous lost in one that blew up prematurely?
On top of all these books, one also worth reading is "The Secret Diary of a U-Boat" by Wolfgang Hirschfeld, who served on U-234, the type XB submarine that was heading to Japan when the war ended, carrying tons of parts (including two Me262's in pieces), passengers and half a ton of uranium oxide.